Mechanical properties of cells are indicators of biological potential, quality and presumptive pathological status. Mammalian oocytes are particularly important cells from the point of view of testing their fertilizing potential and performing in vitro fertilization. However, only occasionally are their mechanical parameters measured. A new method for deformation measurement of in vitro -matured porcine oocytes has been developed and presented in this study. The method was used for multiparametric characterization of gametes using a MEMS-type microcytometer and a new methodology for determining cell deformability. The novel chip design, principle of operation, and fabrication processes are described in the study. Using original analysis of microscopic images with the usage of dedicated software and data analysis algorithms, deformation parameters were determined. Results indicate the relationships between parameters under the influence of cell compression and show that the behaviour of oocytes during measurements depends on the morphological quality of the cumulus-oocyte complexes they originated from.

In this paper, an integrated microprism matrix for light coupling and optical sensing systems is presented. The matrix was fabricated by use of controlled negative pressure glass thermal reflow process by the use of monocrystalline mold. The single glass microprism had height of 250 µm or 350 µm with base width respectively 350 µm or 500 µm. The matrix was formed by 10 × 10 microprisms with distance between the microprisms from 150 µm to 400 µm. It corresponded to total area of the matrixes from 28 mm² to 74 mm². The controlled coupling of the beam into a substrate was obtained through determination of optimal geometric dimensions of microprisms and configuration of a measurement setup. Optimal position of the fluorescence induction light source in relation to the matrixes (0.5 cm to 4.5 cm distance, 30° angle of incidence) and microfluidic channel (4 mm) were determined. The fluorimetric tests (with excitation by 470 nm laser diode in all the experiments) carried out using fluorescein solution, microbeads and porcine oocyte indicated the possibility of using a microprism matrix for fluorimetric image-based 500 nm long-pass detection in lab-on-a-chip platforms.

In this work for the first time MEMS-type deformation microcytometer and a new methodology for the determination of cell deformability is proposed. Novel chip design and methodology allow real-time observation of the cell deformation occurring during compression of oocytes. In addition, software-based analysis of microscopic images allows multiparametric characterization of the investigated cell toward quality assessment of the cell.

It is still a challenge to integrate the optoelectronic technology in microfluidic analytical systems, due to the complex alignment of the optical components within the microchip, or expensive and complicated methods of their fabrication. In this paper, inexpensive, glass microprisms matrix, with high quality surface and precise 54.7° reflection angle is presented. Fabrication and integration of optical components into the substrate is done using conventional microfabrication techniques such as soft lithography and anode bonding. The results of beam intensity measurements propagating within the glass substrate are presented, showing the possibility of controlled coupling of the beam into the substrate using integrated glass optical structures for microfluidic systems.

Transillumination microscopes, often with a simple lens-free optical configuration, combined with lab-on-a-chip devices are useful tools for the characterisation of various biological samples. A key issue with these devices is light transparency across a lab-on-a-chip structure. In this work we achieved this by embedding a glass window in a silicon membrane. Despite light transmission, the membrane could be pressure actuated. A second key issue is software analysis of the images due to the holographic nature of the captured images. In this paper, the technology of the silicon/glass membrane and results of porcine oocyte imaging during deformation are presented and compared with our previous micro-electro-mechanical system cytometer working with a reflective microscope. Thus, a unique device that deforms cells and allows deformation measurements with transillumination was developed.